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A method to estimate probability of disease and vaccine efficacy from clinical trial immunogenicity data. NPJ Vaccines 2021; 6:133. [PMID: 34737322 PMCID: PMC8568947 DOI: 10.1038/s41541-021-00377-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Accepted: 08/11/2021] [Indexed: 12/02/2022] Open
Abstract
Vaccine efficacy is often assessed by counting disease cases in a clinical trial. A new quantitative framework proposed here ("PoDBAY," Probability of Disease Bayesian Analysis), estimates vaccine efficacy (and confidence interval) using immune response biomarker data collected shortly after vaccination. Given a biomarker associated with protection, PoDBAY describes the relationship between biomarker and probability of disease as a sigmoid probability of disease ("PoD") curve. The PoDBAY framework is illustrated using clinical trial simulations and with data for influenza, zoster, and dengue virus vaccines. The simulations demonstrate that PoDBAY efficacy estimation (which integrates the PoD and biomarker data), can be accurate and more precise than the standard (case-count) estimation, contributing to more sensitive and specific decisions than threshold-based correlate of protection or case-count-based methods. For all three vaccine examples, the PoD fit indicates a substantial association between the biomarkers and protection, and efficacy estimated by PoDBAY from relatively little immunogenicity data is predictive of the standard estimate of efficacy, demonstrating how PoDBAY can provide early assessments of vaccine efficacy. Methods like PoDBAY can help accelerate and economize vaccine development using an immunological predictor of protection. For example, in the current effort against the COVID-19 pandemic it might provide information to help prioritize (rank) candidates both earlier in a trial and earlier in development.
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Grady C, Shah S, Miller F, Danis M, Nicolini M, Ochoa J, Taylor H, Wendler D, Rid A. So much at stake: Ethical tradeoffs in accelerating SARSCoV-2 vaccine development. Vaccine 2020; 38:6381-6387. [PMID: 32826103 PMCID: PMC7418641 DOI: 10.1016/j.vaccine.2020.08.017] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2020] [Revised: 08/03/2020] [Accepted: 08/06/2020] [Indexed: 02/08/2023]
Abstract
BACKGROUND A sense of urgency exists to develop vaccines against SARS CoV-2, responsible for numerous global cases and deaths, as well as widespread social and economic disruption. Multiple approaches have been proposed to speed up vaccine development, including accelerated randomized controlled trials (RCT), controlled human challenge trials (CHI), and wide distribution through an emergency use authorization after collecting initial data. There is a need to examine how best to accelerate vaccine development in the setting of a pandemic, without compromising ethical and scientific norms. METHODS Trade-offs in scientific and social value between generating reliable evidence about safety and efficacy while promoting rapid vaccine availability are examined along five ethically relevant dimensions: (1) confidence in and generalizability of data, (2) feasibility, (3) speed and cost, (4) participant risks, and (5) social risks. RESULTS Accelerated individually randomized RCTs permit expeditious evaluation of vaccine candidates using established methods, expertise, and infrastructure. RCTs are more likely than other approaches to be feasible, increase speed and reduce cost, and generate reliable data about safety and efficacy without significantly increasing risks to participants or undermining societal trust. CONCLUSION Ethical analysis suggests that accelerated RCTs are the best approach to accelerating vaccine development in a pandemic, and more likely than other approaches to enhance social value without compromising ethics or science. RCTs can expeditiously collect rigorous data about vaccine safety and efficacy. Innovative and flexible designs and implementation strategies to respond to shifting incidence and test vaccine candidates in parallel or sequentially would add value, as will coordinated data sharing across vaccine trials. CHI studies may be an important complementary strategy when more is known. Widely disseminating a vaccine candidate without efficacy data will not serve the public health nor achieve the goal of identifying safe and effective SARS Co-V-2 vaccines.
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Affiliation(s)
- Christine Grady
- Department of Bioethics, National Institutes of Health Clinical Center, Building 10/1C118, NIH, Bethesda, MD 20892, United States.
| | - Seema Shah
- Lurie Children's Hospital, Northwestern University, Department of Pediatrics, 225 E. Chicago Ave, Chicago, IL 60611, United States.
| | - Franklin Miller
- Weill Cornell Medical College, Weill Cornell Medical College, 1300 York Ave, New York, NY 10065, United States.
| | - Marion Danis
- Department of Bioethics, National Institutes of Health Clinical Center, Building 10/1C118, NIH, Bethesda, MD 20892, United States.
| | - Marie Nicolini
- Department of Bioethics, National Institutes of Health Clinical Center, Building 10/1C118, NIH, Bethesda, MD 20892, United States.
| | - Jorge Ochoa
- Department of Bioethics, National Institutes of Health Clinical Center, Building 10/1C118, NIH, Bethesda, MD 20892, United States.
| | - Holly Taylor
- Department of Bioethics, National Institutes of Health Clinical Center, Building 10/1C118, NIH, Bethesda, MD 20892, United States.
| | - Dave Wendler
- Department of Bioethics, National Institutes of Health Clinical Center, Building 10/1C118, NIH, Bethesda, MD 20892, United States.
| | - Annette Rid
- Department of Bioethics, National Institutes of Health Clinical Center, Building 10/1C118, NIH, Bethesda, MD 20892, United States.
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Sumbria D, Berber E, Rouse BT. Factors Affecting the Tissue Damaging Consequences of Viral Infections. Front Microbiol 2019; 10:2314. [PMID: 31636623 PMCID: PMC6787772 DOI: 10.3389/fmicb.2019.02314] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2019] [Accepted: 09/23/2019] [Indexed: 12/15/2022] Open
Abstract
Humans and animals are infected by multiple endogenous and exogenous viruses but few agents cause overt tissue damage. We review the circumstances which favor overt disease expression. These can include intrinsic virulence of the agent, new agents acquired from heterologous species, the circumstances of infection such as dose and route, current infection with other agents which includes the composition of the microbiome at mucosal and other sites, past history of exposure to other infections as well as the immune status of the host. We also briefly discuss promising therapeutic strategies that can expand immune response patterns that minimize tissue damaging responses to viral infections.
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Affiliation(s)
| | | | - Barry T. Rouse
- Department of Biomedical and Diagnostic Sciences, College of Veterinary Medicine, The University of Tennessee, Knoxville, Knoxville, TN, United States
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Galula JU, Salem GM, Chang GJJ, Chao DY. Does structurally-mature dengue virion matter in vaccine preparation in post-Dengvaxia era? Hum Vaccin Immunother 2019; 15:2328-2336. [PMID: 31314657 PMCID: PMC6816432 DOI: 10.1080/21645515.2019.1643676] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
The unexpectedly low vaccine efficacy of Dengvaxia®, developed by Sanofi Pasteur, and a higher risk of severe diseases after vaccination among dengue-naive children or children younger than 6 years old, have cast skepticism about the safety of dengue vaccination resulting in the suspension of school-based immunization programs in the Philippines. The absence of immune correlates of protection from dengue virus (DENV) infection hampers the development of other potential DENV vaccines. While tetravalent live-attenuated tetravalent vaccines (LATVs), which mimic natural infection by inducing both cellular and humoral immune responses, are still currently favored, developing a vaccine that provides a balanced immunity to all four DENV serotypes remains a challenge. With the recently advanced understanding of virion structure and B cell immune responses from naturally infected DENV patients, two points of view in developing a next-generation dengue vaccine emerged: one is to induce potent, type-specific neutralizing antibodies (NtAbs) recognizing quaternary structure-dependent epitopes by having four components of vaccine strains replicate equivalently; the other is to induce protective and broadly NtAbs against the four serotypes of DENV with a universal vaccine. This article reviews the studies related to these issues and the current knowledge gap that needs to be filled in.
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Affiliation(s)
- Jedhan Ucat Galula
- Graduate Institute of Microbiology and Public Health, College of Veterinary Medicine, National Chung Hsing University , Taichung , Taiwan
| | - Gielenny M Salem
- Graduate Institute of Microbiology and Public Health, College of Veterinary Medicine, National Chung Hsing University , Taichung , Taiwan
| | - Gwong-Jen J Chang
- Division of Vector-Borne Diseases, Centers for Disease Control and Prevention, US Department of Health and Human Services , Fort Collins , CO , USA
| | - Day-Yu Chao
- Graduate Institute of Microbiology and Public Health, College of Veterinary Medicine, National Chung Hsing University , Taichung , Taiwan
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